Gypsum, potash salt and sodium salt are formed as a result of evaporation especially in arid region.

Evaporite minerals (gypsum, anhydrite and halite) are precipitated within the sediments by evaporation of capillarity brines (evaporite pumping) and as surface crusts.

The first mineral to crystallize from evaporation of seawater is calcium carbonate (CaCO3), usually as calcite, but at other times aragonite may form. Next is calcium sulfate either as gypsum (CaSO4 · 2H2O) or anhydrite (CaSO4). The next most abundant evaporite mineral is halite (NaCl), commonly known as rock salt.

When water evaporates, it leaves behind a solid precipitate of minerals, as shown in Figure below. When the water in glass A evaporates, the dissolved mineral particles are left behind.

About EvaporiteHide Sedimentary rocks containing non-carbonate salts. Examples include gypsum, anhydrite, rock salt, and various nitrates and borates. The term sometimes includes rocks developed by metamorphism or transport of other evaporites.

Evaporites are layered crystalline sedimentary rocks that form from brines generated… Typically, evaporite deposits occur in closed marine basins where evaporation exceeds inflow. The deposits often show a repeated sequence of minerals, indicating cyclic conditions with a mineralogy determined by solubility.

Rocks formed by the evaporation of water are called evaporites – gypsum, anhydrite, halite (common salt). This evaporation may occur in either shallow basins on land or in the sea. The less-soluble compounds (those that dissolve less readily in water) are deposited first. …

Chert is a sedimentary rock consisting almost entirely of silica (SiO 2), and can form in a variety of ways. Biochemical chert is formed when the siliceous skeletons of marine plankton are dissolved during diagenesis, with silica being precipitated from the resulting solution.

Thick beds of chert occur in deep marine deposits. These thickly bedded cherts include the novaculite of the Ouachita Mountains of Arkansas, Oklahoma, and similar occurrences in Texas and South Carolina in the United States.

Chert has four diagnostic features: the waxy luster, a conchoidal (shell-shaped) fracture of the silica mineral chalcedony that composes it, a hardness of seven on the Mohs scale, and a smooth (non-clastic) sedimentary texture.

Some limestone contains chert, which is very, very hard silica (like flint)….Non-Clastic Sedimentary Rocks.

Calcite is the main component of limestone rocks and its varieties like oolitic limestone, fossiliferous limestone, coquina and marble. The calcite mineral is made of calcium carbonate which reacts with acid. Other varieties of calcium carbonate minerals such as aragonite and dolomite will also fizz during this test.

Quartz is a mineral, and it does not rust. Vinegar does not affect quartz since it is a weak acid, but it can dissolve mineral impurities coating quartz. You can clean quartz with dilute vinegar but be careful not to leave it wet with either vinegar or water for long.

Quartz crystals have no cleavage; therefore, the crystals do not break along the crystal face. If broken, quartz exhibits a conchoidal fracture. Because of the fracture, quartz crystals will break into sharp pieces.

Calcium carbonate reacts with an acid to produce bubbles on the surface of the crystal. Quartz does not react to a dilute acid.

Determining the Difference Between Fluorite and Quartz Fluorite is a four on the hardness scale, whereas quartz is a seven, which is much harder. Fluorite will scratch if you scratch it with a normal knife blade because a blade has a hardness of 5.5. Quartz will not scratch if you try to score it with a knife blade.

Sometimes you may have to grind up some of the sample into powder to increase the surface before you can see the reaction – especially when using a weak acid like vinegar. Feldspar is a silicate mineral not composed of calcium carbonate. Therefore it is harder than your knife, and doesn’t fizz.

Limestone. Limestone is a very common sedimentary rock. Limestone fizzes with the application of dilute hydrochloric acid because it contains calcite.

Chemical Rocks Chemical sedimentary rocks are identified by identifying the mineral from which they are composed. In this lab there are four minerals that need to be identified – quartz, halite, gypsum and calcite. Quartz has a hardness of 7 and is very difficult to scratch, even with a good quality knife blade.

1 Answer. Sedimentary rocks have layers because of different depositions of sediments (small broken pieces of rocks) over time. These are your “sediments”. You get a large clear boc, and dump in all of your dirt.

Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks. Sedimentary rocks are deposited in layers as strata, forming a structure called bedding. Sedimentary rocks are also important sources of natural resources including coal, fossil fuels, drinking water and ores.

Sedimentary Rock Textures. In clastic sediments the sedimentary texture includes the grain size, rounding, and sorting of the grains, all of which are related to what happened to the sediment during the weathering-to-deposition process.